Cut-off-valve mechanism.



W. Y. MOFFAT.

GUT-OFF VALVE MECHANISM. APPLICATION PILE DEC. 23, 1'909.

1,086,071 I Patented Feb. 3, 1914,

2 SHEETS-SHEET 1.

'W. Y. MOFFAT.

GUT-OFF VALVE MECHANISM.

APPLICATION FILED D110. 23, 1909.

1 ,O86,071 Patented Feb. 3,1914.

2 SHEETS-SHEET 2.

Smwwm WILLIAM Y. MOFFAT, or :sQBANIQL BENNSYLV IA,

TEA rum omer-v, A CORPORATION nssrenon T0 INTERNATIQNAL or JERSEY.

GUT-OFF-VALVE ISM.

Specification of Letters Patent.

Application filedilecembcr 23, 1909. Serial ar 534,681.

To all whom itmage concern FAT, a citizen of the :United States,residing at Scranton, in the county of Lackawanna and State ofPennsylvania, have invented: certain new and useful Improvements m1Cut-Oif-Valve Mechanisms; and I do here:

by declare the following tobe a full, clear, and exact description oftheinvention, such as will enable others skilled in the art to which itappertains to make and use the same. A

This invent-ion relates to cut ,ofi valve mechanisms for steam pumps,and has for an object to provide improved gear Whereby the valves aregiven a complete opening and are closed to out 01f sooner as mayberequired without elfecting the initial opening of the port.

A further object of the invention is to provide in a device of the classimproved means whereby the valves upon opposite sides of the pump may besimultaneously and similarly adjusted.

A further object of the invention is to provide a controlling device ofthe class adapted to be operated selectively by manual means orautomatic devices.

With these and other objects in view, the invention comprises certainnovel constructions, combinations and arrangements of parts, as will behereinafter fully described and claimed.

In the drawings, Figure 1 is a view in elevation of one side of afragment of a conventional steam pump with the cut off valve appliedthereto. Fig. 2 is a view of a similar pump showing the valves insection. Fig. 3 is a top plan View of the form of pump shown at Figs. 1and 2. Fig. 4 is a slight modification of the apparatus as shown atFigs. 1 to 8 inclusive.

Like characters of reference designate corresponding parts throughoutthe several parts.

As shown in the drawings the device is applicable to the usual andordinary pumps, one of which is shown conventionally with the cylinders10 and pistonrod 11, with the usual main valves 12 and the cut offvalves 13. The cut off valves 13 are, of course, provided with the usualshafts or stems 14 and with the crank arms 15 in the usual manner.

Between the cut off valves 13 a rocker 16 is fulcrumed as at 17employing the usual f andordinary fulcrum stud therefor, but the Be itknown that I, WILLIAM Y. M01- rocker instead of being constructed asusually employed is provided at its-upper end With means as the inturnedflanges 18 for engaging and'maintaining a block 19 slidab ly therein.The block 19 is provided with a pin 20 upon which are pivoted the links21 extending in. opposite directions to and pivoted at 22 to theextremities of the crank arms 15. The rocker 16 is actuated in the usualmanner by means of the link 22 from the crank 23, and it will beapparent that as the rocker 1.6 is moved the crank arms 15 will also bemoved and move there with the valves 13. It will also be apparent thatas the block 19 is moved nearer to or farther from the fulcrum 17, themotion of the valves will be respectively decreased or increased. Toaccomplish the adjustment of the block 19 a link 24 is also pivoted uponthe pin 20 and its upper end is pivoted to an arm 25 carried upon ashaft 26, which extends transversely across the pump structure, one ofthe arms 25 being provided at each end of the shaft, that is to say,upon each side of the pump.

-For controlling the position of the arm 25, means is provided formoving the shaft 26 rotatably. Such means is shown by the automaticcontrol indicated by the cylinder 27 having-a piston 28 mounted thereinand pivotally connected with an arm 29 carried rigidly upon the shaft 26and with a weight .30 tending to normally hold the lever down and theblock 19 in the position as indicated at Fig. 1. The cylinder 27 andpiston 28, may be of the common form described in United States LettersPatent No. 312,138 and well known under the name Mason pump governor,the raising of the piston 28, in case of excessive speed, rocking shaft26 through lever 29, so as to raise arms 25 and move blocks 19 upward inrockers 16 for earlier cut-off, this move-- ment of the blocks 19positioning them farther from the rocker fulcrum 17 so as to increasethe movement of the cut-off valves and secure the full opening of theportswith earlier cut-off.

The blocks 19 may be adjusted manually,

and the engine provided with the automatic control or not, as desired.For the purpose of manual control a hand wheel '31 is provided on shaft26, this wheel preferably carrying a bolt 32 adapted to engage in theslot 33 of a bracket 34 of the pump frame,

Patented Feb. 3, 1914..

so as to limit the movement of the hand wheel and shaft 26 on theiradjustment in either direction. The hand wheel is also preferablyprovided with a pointer 35 moving adjacent to a graduated scale 36whereby the position of the block and consequently the adjustment of thevalves may be determined by reading from the pointer and scale.

It will be apparent that instead of applying the sliding block and guidemechanism to the rocker 16 it may be applied in place of the crank 23 asshown at Fig. 4:. In this embodiment the crank is replaced by theflanged arm 87 with the block 38 slidablc therein and controlled by thelink 2 1, which link is in turn controlled similarly to the link 24. Theblock 38 is connected with the rocker by means of the link 22, therocker 16 being of the usual type ordinarily employed upon suchstructures.

It will be apparent that the movement of the sliding block 38 in theguide arm 37 will accomplish nearly the same result as the movement ofthe block 19 in the guide 18. It is found, however, that by the use ofthe structure shown at Fig. 1 better results are attained in that thevalves are at all times given the full initial opening and only theclosing effected by the adjustment.

Considering now the central position of the rocker 16 and the crank arms15, it is to be noted that the parts are so located and arranged thatthe links 21 make a relatively flat angle with the horizontal, in thevarious positions to which they may be adjusted in actual practice.Therefore, during the adjustment of the sliding block in or out from thefulcrum 17, the cut-off valve itself will be but very slightly shiftedor displaced relative to its port, the amount of such displacement beingproportional to the difference of the versed sines of the angles of thelinks before and after the change, whereas the relation of the amount ofmovement of the valve, after a change of the adjustment, to the amountof its movement prior to the change, is proportional to the differencein the sines of the angles of the links before and after the change.Since with flat angles the rate of change of the sine is very great,compared with the rate of change of its versed sine, it is clear that byapplicants arrangement a material change of the amount of movement ofthe valve may be made by shifting the pivotal connection 20 of the linksin or out on the rocker, with out substantial displacement of the cutoffvalve from its normal initial position relative to the port.Consequently, the said cut-off valve may always allow its port to remainfully open at the initial position of the valve, notw1thstand1ng theadjustment 5 of the pivotal point of connection of the links to therocker.

It will be observed that the movement illustrated in Fig. l isparticularly advan tageous because the ports are so arranged that thepointof connection 20 of the links to the sliding block 19 may beadjusted, not only above but also below the horizontal plane through theconnections 22 of the links and crank arms 15. lhus, as will be seenfrom said Fig. 1, the point of connection 20 may be shifted from a pointlying a certain distance below the horizontal plane through the points22 to a position lying an equal distance above said horizontal plane,and in both of said positions the cut-off valves will be in identicalpositions relative to the ports, yet the amount of movement of thevalves will be materially different. Therefore, since a greater amountof movement of the cut-off valve implies a greater speed of movement, itfollows that with such greater movement the valve, traveling from itsinitial position where the port is wide open, will close said portsooner than it will when having a smaller amount of movement, andconsequently a relatively slower speed.

What I claim is 1. In a cut-off valve mechanism, rocking cut-off valves,a rocker pivoted between the valves, arms connecting the rocker with thevalves, and means for actuating the valves through the rocker includinga member adjustable for varying the point of cut-off and arranged sothat the movement of the valves is increased on adjustment of saidmember for earlier cut-off.

2. In a cut-off valve mechanism, rocking cut-off valves, a rockerpivotedbetween the valves, a member adjustable longitudinally upon therocker, arms connecting the adjustable member with the valves in such amanner that the movement of the valves is increased on adjustment of themember for earlier cut-off, and means for operating the rocker.

3. In a cut-off valve mechanism, rocking cut-off valves, leversextending from the valve stems, a rocker pivoted between the valves, amember adjustable upon the rocker toward its fulcrum for later cut-01fand away from its fulcrum for earlier cut-off, and arms pivoted to thefulcrum and to the levers and arranged to increase the throw of thelevers when the adjustable member is adjusted for earlier cut-off.

In testimony whereof I affix my signature in presence of two witnesses.

VJILLIAM Y. MOFFAT.

\Vitn esses L. L. Monninn, J 01in L. Fnnrcnnn.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents,

Washington, I). C.

